Without natural genetic boundaries to guide us, human racial categories remain a product of our choices. Those choices are not totally arbitrary, biologically meaningless, or without utility. But because they are choices, we have some leeway in how we define and apply racial categories. We shouldn't deceive ourselves; how we define race does not just reflect biology, it reflects culture, history, and politics as well.

Many people, perhaps most, think of “race” as an objective reality. Historically, however, racial categorization has been unstable, contradictory, and arbitrary. Consider the term “passing.” Most of us immediately picture a light-skinned person who is “hiding” their African ancestry. Many would go further and accuse that person of denying their “real” racial identity. Yet few people would accuse a dark-skinned person who has an Anglo ancestor of trying to pass for “black,” and thereby denying their “true” Anglo roots!

So why is a white person with an African ancestor presumed to be “really” black? In fact, in this day of DNA testing, it’s become increasingly clear that many more white-identified people have a “drop” or two of African ancestry than most ever imagined. Are lots of white folks (or are they black?) “passing,” then, without even knowing it?..